/*这是2012.1.3在官方网站http://processors.wiki.ti.com/index.php?title=MSP430_LaunchPad_(MSP-EXP430G2)#Complete_Projects 下载的，版本号：slac435b *中文为本人http://wangfuchong.com添加的注释，切记不一定正确，仅供尽可能地快速了解程序的结构。 ×还是有一些疑惑，总觉得有不够严谨的可能，大家帮助分析。 * main.c * * MSP-EXP430G2-LaunchPad User Experience Application * * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/ * * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the * distribution. * * Neither the name of Texas Instruments Incorporated nor the names of * its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ /****************************************************************************** * MSP-EXP430G2-LaunchPad User Experience Application * * 1. Device starts up in LPM3 + blinking LED to indicate device is alive * + Upon first button press, device transitions to application mode * 2. Application Mode * + Continuously sample ADC Temp Sensor channel, compare result against * initial value * + Set PWM based on measured ADC offset: Red LED for positive offset, Green * LED for negative offset * + Transmit temperature value via TimerA UART to PC * + Button Press --> Calibrate using current temperature * Send character '? via UART, notifying PC * * Changes: * * 1.2 + Updated register naming conventions to reflect latest standard by TI * e.g.: CCR0 --> TACCR0, CCTL0 --> TACCTL0 * + Changed method to capture TAR value into TACCR0 by using capture a * SW-triggered event. [Changing TACCR input from GND to VCC] × 1.2是与版本slac435a相比新更改的部分 * 1.1 + LED1 & LED2 labels changed so that Green LED(LED2) indicates sampled * temperature colder than calibrated temperature and vice versa * with Red LED (LED1). * + Turn off peripheral function of TXD after transmitting byte to * eliminate the extra glitch at the end of UART transmission * 1.0 Initial Release Version * * Texas Instruments, Inc. ******************************************************************************/ #include "msp430g2231.h" #define LED1 BIT0 //绿灯，BIT0，BIT6之类的是宏定义，请在头文件"msp430g2231.h"中查看 #define LED2 BIT6 //红灯，参见MSP-EXP430G2 LaunchPad Experimenter Board User's Guide #define LED_DIR P1DIR #define LED_OUT P1OUT #define BUTTON BIT3 //P1.3为板上按键S2 #define BUTTON_OUT P1OUT //端口输出寄存器 #define BUTTON_DIR P1DIR //端口方向控制寄存器 #define BUTTON_IN P1IN //端口输入寄存器 #define BUTTON_IE P1IE //端口中断允许寄存器 #define BUTTON_IES P1IES //端口中断触发沿控制寄存器 #define BUTTON_IFG P1IFG //端口中断标志寄存器 #define BUTTON_REN P1REN //端口上下拉电阻使能控制寄存器 #define TXD BIT1 // TXD on P1.1 #define RXD BIT2 // RXD on P1.2 #define APP_STANDBY_MODE 0 //待机模式标志，也就是接上电源（或USB）后红绿灯交替闪的状态 #define APP_APPLICATION_MODE 1 //应用模式标志，也就是待机模式时按按键后进入的状态，也就是测量温度 #define TIMER_PWM_MODE 0 #define TIMER_UART_MODE 1 //串口模式状态 #define TIMER_PWM_PERIOD 2000 #define TIMER_PWM_OFFSET 20 #define TEMP_SAME 0 #define TEMP_HOT 1 #define TEMP_COLD 2 #define TEMP_THRESHOLD 5 // Conditions for 9600/4=2400 Baud SW UART, SMCLK = 1MHz #define Bitime_5 0x05*4 // ~ 0.5 bit length + small adjustment #define Bitime 13*4//0x0D #define UART_UPDATE_INTERVAL 1000 //主循环次数进行一次串口发送温度值 unsigned char BitCnt; unsigned char applicationMode = APP_STANDBY_MODE; //功能模式标志，初始值为待机模式 unsigned char timerMode = TIMER_PWM_MODE; unsigned char tempMode; unsigned char calibrateUpdate = 0; unsigned char tempPolarity = TEMP_SAME; unsigned int TXByte; /* Using an 8-value moving average filter on sampled ADC values */ long tempMeasured[8]; //定义数组以计算8次10位ADC温度采样的平均值 unsigned char tempMeasuredPosition=0; //温度测量值数组索引 long tempAverage; //8次10位ADC温度采样的平均值 long tempCalibrated, tempDifference; void InitializeLeds(void); //IO端口初始化，设置两颗LED对应的端口并两设置为熄灭初始状态 void InitializeButton(void); //IO端口初始化，配置按键 void PreApplicationMode(void); //进入待机模式，红绿灯交替闪，等待按键 Blinks LED, waits for button press void ConfigureAdcTempSensor(void); //配置温度传感器模数转换 void ConfigureTimerPwm(void); //配置定位器为PWM模式 void ConfigureTimerUart(void); //配置定时器为Uart模式 void Transmit(void); //串口发送子程序 void InitializeClocks(void); //初始化时钟系统 void main(void) { unsigned int uartUpdateTimer = UART_UPDATE_INTERVAL; //主循环次数进行一次串口发送温度值 unsigned char i; WDTCTL = WDTPW + WDTHOLD; // 停止看门狗 Stop WDT InitializeClocks(); //初始化时钟系统 InitializeButton(); //配置按键 InitializeLeds(); //设置端口并两设置两颗LED对应为熄灭初始状态 PreApplicationMode(); //进入待机模式，红绿灯交替闪，等待按键 Blinks LEDs, waits for button press //执行PreApplicationMode()将进入低功耗模式，程序停止在此，直到有按键按下 /* 进入应用模式 Application Mode begins */ applicationMode = APP_APPLICATION_MODE; //功能模式标志变成应用模式 ConfigureAdcTempSensor(); //配置温度传感器模数转换 ConfigureTimerPwm(); //配置定位器PWM模式 __enable_interrupt(); //使能全局中断 Enable interrupts. /* Main Application Loop */ while(1) { ADC10CTL0 |= ENC + ADC10SC; //ADC使能，ADC开始转换一次 Sampling and conversion start __bis_SR_register(CPUOFF + GIE); //进入省电模式LPM0，等待AD转换完成中断 LPM0 with interrupts enabled /* Moving average filter out of 8 values to somewhat stabilize sampled ADC */ tempMeasured[tempMeasuredPosition++] = ADC10MEM; //将温度采样值存入温度值数组下一位 if (tempMeasuredPosition == 8) tempMeasuredPosition = 0; 复位温度采样值数组索引 tempAverage = 0; for (i = 0; i < 8; i++) tempAverage += tempMeasured[i]; //累加温度采样值数组各值 tempAverage >>= 3; //除以8得到平均值 Divide by 8 to get average if ((--uartUpdateTimer == 0) || calibrateUpdate ) //如果主循环了UART_UPDATE_INTERVAL次或者参考温度按键按过 { ConfigureTimerUart(); if (calibrateUpdate) { TXByte = 248; // A character with high value, outside of temp range Transmit(); //串口发送值248表示按键按下进行了校准参考 calibrateUpdate = 0; //复位参考温度校准标志变量 } TXByte = (unsigned char)( ((tempAverage - 630) * 761) / 1024 ); //计算温度华氏值 Transmit(); //串口发送华氏温度值 uartUpdateTimer = UART_UPDATE_INTERVAL; //复位循环计数变量 ConfigureTimerPwm(); //配置定时器回PWM模式 } tempDifference = tempAverage - tempCalibrated; //计算相对于参考温度的差值 if (tempDifference < -TEMP_THRESHOLD) //如果采样温度值低于参考温度值差值TEMP_THRESHOLD { tempDifference = -tempDifference; //差值取正 tempPolarity = TEMP_COLD; //极性变量设为值TEMP_COLD LED_OUT &= ~ LED1; //LED1绿灯置灭 } else if (tempDifference > TEMP_THRESHOLD) //如果采样温度值高于参考温度值差值TEMP_THRESHOLD { tempPolarity = TEMP_HOT; //极性变量设为值TEMP_COLD LED_OUT &= ~ LED2; //LED2红灯置灭 } else //如果相对于参考温度值偏差没有超过阈值TEMP_THRESHOLD { tempPolarity = TEMP_SAME; //性变量设为值TEMP_SAME TACCTL0 &= ~CCIE; //关TACCTL0中断使能 TACCTL1 &= ~CCIE; //关TACCTL1中断使能 LED_OUT &= ~(LED1 + LED2); //置两灯皆灭 } if (tempPolarity != TEMP_SAME) //如果相对于参考温度值偏差超过阈值TEMP_THRESHOLD { tempDifference <<= 3; //温度偏差值乘以8 tempDifference += TIMER_PWM_OFFSET; //加上一个偏置值 TACCR1 = ( (tempDifference) < (TIMER_PWM_PERIOD-1) ? (tempDifference) : (TIMER_PWM_PERIOD-1) ); //置TACCR1，最大为TIMER_PWM_PERIOD-1。 //TACCR1值控制亮的时间，定时器计数到TACCR1在中断中将关闭灯，在TACCR0中断中亮灯 TACCTL0 |= CCIE; //开TACCTL0中断使能 TACCTL1 |= CCIE; //开TACCTL1中断使能 } } //返回主循环 } //进入待机模式，红绿灯交替闪，等待按键 void PreApplicationMode(void) { LED_DIR |= LED1 + LED2; //p1.0和P1.6口为输出 LED_OUT |= LED1; //绿灯亮 To enable the LED toggling effect LED_OUT &= ~LED2; //红灯灭 BCSCTL1 |= DIVA_1; //辅助时钟分频设置为2 ，ACLK=6KHz BCSCTL3 |= LFXT1S_2; //辅助时钟源选择VLOCLK，12KHz //ACLK = VLO TACCR0 = 1200; // TACTL = TASSEL_1 | MC_1; //定时器时钟源选择辅助时钟ACLK，增计数模式 // TACLK = SMCLK, Up mode. TACCTL1 = CCIE + OUTMOD_3; //捕获/比较控制寄存器1设置为比较模式，输出模式为“置位/复位” ，中断允许 // TACCTL1 Capture Compare TACCR1 = 600; __bis_SR_register(LPM3_bits + GIE); // LPM0 with interrupts enabled ？？低功耗模式LPM3 //此时cpu停止，等待中断，如果是比较1中断，则进入中断程序：ta1_isr(void)，因为是CC1。 //如果是按键中断，则进入PORT1_ISR(void)中断服务程序，在PORT1_ISR(void)中将退出此低功耗模式 } //配置温度传感器模数转换 void ConfigureAdcTempSensor(void) { unsigned char i; /* Configure ADC Temp Sensor Channel */ ADC10CTL1 = INCH_10 + ADC10DIV_3; //选择ADC通道为温度传感器，时钟4分频 // Temp Sensor ADC10CLK/4 ADC10CTL0 = SREF_1 + ADC10SHT_3 + REFON + ADC10ON + ADC10IE; // VR+ = VREF+ and VR- = VSS，采样保持时间=64×ADC10CLK周期，打开内部参考电压，打开ADC模块，ADC中断允许 __delay_cycles(1000); //延时等待ADC参考电压建立 // Wait for ADC Ref to settle ADC10CTL0 |= ENC + ADC10SC; //ADC使能，ADC开始转换一次 // Sampling and conversion start __bis_SR_register(CPUOFF + GIE); //进入省电模式LPM0，等待AD转换完成中断 // LPM0 with interrupts enabled tempCalibrated = ADC10MEM; for (i=0; i < 8; i++) tempMeasured[i] = tempCalibrated; tempAverage = tempCalibrated; //第一次转换，平均温度取样值和校准值相等 } //配置定位器为PWM模式 void ConfigureTimerPwm(void) { timerMode = TIMER_PWM_MODE; TACCR0 = TIMER_PWM_PERIOD; // TACTL = TASSEL_2 | MC_1; //定时器时钟源选择辅助时钟SMCLK，增计数模式 // TACLK = SMCLK, Up mode. TACCTL0 = CCIE; TACCTL1 = CCIE + OUTMOD_3; //捕获/比较控制寄存器1设置为比较模式，输出模式为“置位/复位” ，中断允许 ？？OUTMOD_3有什么用？ // TACCTL1 Capture Compare TACCR1 = 1; } //配置定时器为Uart模式 void ConfigureTimerUart(void) { timerMode = TIMER_UART_MODE; // Configure TimerA0 UART TX TACCTL0 = OUT; //输出为高电平 // TXD Idle as Mark TACTL = TASSEL_2 + MC_2 + ID_3; //定时器时钟源选择辅助时钟SMCLK，连续计数模式 ，时钟8分频 // SMCLK/8, continuous mode P1SEL |= TXD + RXD; //打开P1.1，P1.2引脚特殊功能 P1DIR |= TXD; //P1.1端口方向为输出 } //串口发送子程序 Function Transmits Character from TXByte void Transmit() { BitCnt = 0xA; //低电平起始位+8位数据+高电平停止位共10位 // Load Bit counter, 8data + ST/SP /* Simulate a timer capture event to obtain the value of TAR into the TACCR0 register */ //模仿捕捉模式以获得当前的TAR值赋予TACCR0 TACCTL0 = CM_1 + CCIS_2 + SCS + CAP + OUTMOD0; //上升沿捕捉，输入源为GND，输出模式置位模式 //capture on rising edge, initially set to GND as input // clear CCIFG flag TACCTL0 |= CCIS_3; //改变输入源为VCC，相当于输入源上升沿变化，触发捕捉//change input to Vcc, effectively rising the edge, triggering the capture action while (!(TACCTL0 & CCIFG)); //查询TACCTL0中断标志位 //allowing for the capturing//updating TACCR0. TACCR0 += Bitime ; //首位发送延时 // Some time till first bit TXByte |= 0x100; //增加停止位 // Add mark stop bit to TXByte TXByte = TXByte << 1; //左移一位右边添加一位0表示起始位 // Add space start bit TACCTL0 = CCIS0 + OUTMOD0 + CCIE; //比较模式，OUTMOD0=OUTMOD_1输出模式为置位模式，清中断标志，中断允许 // TXD = mark = idle while ( TACCTL0 & CCIE ); //循环，直到反复中断中完成发送 // Wait for TX completion } //TACCR0中断专用， Timer A0 interrupt service routine #pragma vector=TIMERA0_VECTOR __interrupt void Timer_A (void) { if (timerMode == TIMER_UART_MODE) //定时器为Uart模式 { TACCR0 += Bitime; //TACCR0加上一位串口数据所需的计数量，准备下一次中断 // Add Offset to TACCR0 if (TACCTL0 & CCIS0) //为什么要？ TX on CCI0B? { if ( BitCnt == 0) //如果全部发送完成 { P1SEL &= ~(TXD+RXD); //取消引脚特殊功能 TACCTL0 &= ~ CCIE ; //关闭中断使能 // All bits TXed, disable interrupt } else { TACCTL0 |= OUTMOD2; //注意是“或”运算 ，设置成复位模式（原来为复位OUTMOD0，现在为OUTMOD_3） // TX Space if (TXByte & 0x01) TACCTL0 &= ~ OUTMOD2; //如果发送的是1，输出模式转为置位模式 // TX Mark TXByte = TXByte >> 1; //右移一位，准备下一位发送 BitCnt --; //发送位计数 } } } else //定位器为PWM模式 { if (tempPolarity == TEMP_HOT) LED_OUT |= LED1; //如果相对于参考温度偏差为正，LED1绿灯置为亮 if (tempPolarity == TEMP_COLD) LED_OUT |= LED2; //如果相对于参考温度偏差为负，LED2红灯置为亮 TACCTL0 &= ~CCIFG; //清中断标志位??有必要么?不是自动清除？ } } //TACCR1和定时器共用中断向量 #pragma vector=TIMERA1_VECTOR __interrupt void ta1_isr(void) { TACCTL1 &= ~CCIFG; //捕获比较中断标志CCIFG。比较模式：定时器 TAR 值等于寄存器 CCR1 值时CCIFG置位。需手动清除 if (applicationMode == APP_APPLICATION_MODE) LED_OUT &= ~(LED1 + LED2); //如果程序运行至是应用模式，置两灯皆灭 else LED_OUT ^= (LED1 + LED2); //如果是待机模式，异或，原来两个灯本来就是一亮一灭的，所以反复中断的效果是交替闪烁。PreApplicationMode(void)中 } void InitializeClocks(void) { BCSCTL1 = CALBC1_1MHZ; //用FLASH中信息存贮器A段的校准数据设置基本时钟系统控制寄存器 1 // Set range DCOCTL = CALDCO_1MHZ; //用FLASH中信息存贮器A段的校准数据设置 DCO 控制寄存器，设置DCO校准为1MHz，详细原理请查看G2系列芯片的Users Guide BCSCTL2 &= ~(DIVS_3); //SMCLK为0分频DCO // SMCLK = DCO = 1MHz } void InitializeButton(void) // Configure Push Button { BUTTON_DIR &= ~BUTTON; //按键对应的端口方向为输入 BUTTON_OUT |= BUTTON; //设置输出寄存器对应的按键位为1 BUTTON_REN |= BUTTON; //使能上拉电阻，因为对应的输出寄存器位为1。反之如果对应的输出寄存器位为0则自动选择下拉电阻。 BUTTON_IES |= BUTTON; //选择下降沿中断 BUTTON_IFG &= ~BUTTON; //中断标志清零 BUTTON_IE |= BUTTON; //按键中断允许 } //设置两颗LED对应的端口并两设置为熄灭初始状态 void InitializeLeds(void) { LED_DIR |= LED1 + LED2; //P1DIR=BIT1+BIT6 p1.0和P1.6口为输出 LED_OUT &= ~(LED1 + LED2); //两个LED低电平熄灭 } /* ************************************************************* * Port Interrupt for Button Press * 1. During standby mode: to exit and enter application mode * 2. During application mode: to recalibrate temp sensor * *********************************************************** */ #pragma vector=PORT1_VECTOR __interrupt void PORT1_ISR(void) { BUTTON_IFG = 0; //清P1口所有中断标志 BUTTON_IE &= ~BUTTON; //禁止按键中断使能，防抖动，经过看门狗定时器延时在看门狗定时器中断中再打开 /* Debounce */ WDTCTL = WDT_ADLY_250; //=(WDTPW+WDTTMSEL+WDTCNTCL+WDTSSEL+WDTIS0)看门狗设置为定时器模式，计数清零，时钟源为辅助时钟ACLK，定时周期为Taclk×32768 IFG1 &= ~WDTIFG; //清看门狗定时器中断标志 /* clear interrupt flag */ IE1 |= WDTIE; //使能看门狗定时器中断 if (applicationMode == APP_APPLICATION_MODE) //如果是应用模式 { tempCalibrated = tempAverage; //？？？如果中断发生在for (i = 0; i < 8; i++) tempAverage += tempMeasured[i];不是错了么？ calibrateUpdate = 1; //参考温度校准标志变量 } else { applicationMode = APP_APPLICATION_MODE; //由待机模式切换到应用模式 // Switch from STANDBY to APPLICATION MODE __bic_SR_register_on_exit(LPM3_bits); //退出低功耗模式LPM3 } } // WDT Interrupt Service Routine used to de-bounce button press #pragma vector=WDT_VECTOR __interrupt void WDT_ISR(void) { IE1 &= ~WDTIE; //禁止看门狗定时器中断 /* disable interrupt */ IFG1 &= ~WDTIFG; //清看门狗定时器中断标志 /* clear interrupt flag */ WDTCTL = WDTPW + WDTHOLD; //使看门狗关闭状态 /* put WDT back in hold state */ BUTTON_IE |= BUTTON; //使能按键中断 /* Debouncing complete */ } // ADC10 interrupt service routine #pragma vector=ADC10_VECTOR __interrupt void ADC10_ISR (void) { __bic_SR_register_on_exit(CPUOFF); //退出省电模式 // Return to active mode } 复制代码
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